DE10248454A1 - Vehicular power transmission control / control system - Google Patents

Abstract

A vehicle power transmission control system comprises a continuously variable transmission (CVT), which transmits the output power of an engine (E) to the wheels, a starting clutch (5), which controls the power transmission in the continuously variable transmission, an electric motor / generator (M ), which can support the motor in the rotary drive and a hydraulic pump (P), which is connected to the output shaft (Es) of the motor (E). When the vehicle that has stopped with the engine subsequently stopped under an idling elimination control is restarted, the power transmission control system controls the electric motor / generator (M) to drive the output shaft (Es) of the engine (M ) to which no fuel supply is permitted, in order to drive the pump (P). When the starting clutch (5) receiving hydraulic pressure from the hydraulic pump (P) starts to engage, the power transmission control system then starts to operate the engine (E).

Description

The present invention relates to a control system for Control / regulation of the power transmission by a power transmission system, the can perform engine idle elimination control when the vehicle stops. Furthermore, the present invention relates in particular a power transmission control system that is controlled by a Control is characterized, which the vehicle by indenting a Start clutch after restarting during the Idle elimination control / stopped engine starts again.

In general, automobiles have a construction for transmission the driving force from an engine to wheels through a power transmission. In addition, there are many for the purpose of improving economy Vehicles today with idle elimination control equipped, in which the operation of the engine is stopped when that Vehicle stops (see, for example, Japanese Patent No. 3011069 and Japanese Patent Laid-Open No. 2000- 272380).

Generally, a power transmission (transmission) includes a hydraulic one actuated frictional engagement element (hydraulic clutch, hydraulic Brake, etc.) used to transmit the driving force to steer from an engine to wheels. In a case where one Idle elimination control / transmission control is carried out, the hydraulic pump stops, which is a hydraulic one Pressure applies to the frictional engagement element when the engine is operating is stopped, and therefore the frictional engagement element itself also stops because of the design of the transmission, in which the pump from the motor is driven. If the engine to start the vehicle from the stopped state during idle elimination control is started again, the started engine drives the pump again, which supplies the hydraulic pressure to the frictional engagement element. Here the start of the engagement of the friction engagement element follows the start of the Engine. Because of the delay in the intervention of the Frictional engagement elements with respect to the start of the engine can immediately after the restart the engine and before the actual intervention of the Frictional engagement elements occur when the engine is cranking up or running through, which affects the driving performance of the vehicle.

To solve this problem, this includes the Japanese patent No. 3011069, a power transmission system disclosed an electricity Generating electric motor means (electric motor / generator). If the engine to Starting the vehicle from the stop state during the Idle elimination control is started again Electric motor generator operated to load the engine (to generate electricity, to prevent engine runaway occurs). Furthermore, in Japanese Patent Laid-Open No. System disclosed in 2000-272380 provided with a control / regulation, to throttle the output power of the engine when the engine is out of the stopped state under the idle elimination control is started again until the engagement of the friction engagement element starts. In particular, the throttle valve is used in this control the engine is kept closed, so that the fuel supply to Prevention of engine runaway is throttled.

However, when the one in Japanese Patent No. 3011069 disclosed system the vehicle under the idle elimination control regulation would be stopped and started repeatedly, the Electric motor / generator may heat up or even overheat. Such Action can reduce the durability of the motor / generator. If consequently the electric motor / generator heats up, then one Safety device actuated to control idle elimination control prevent. This leads to reduced fuel efficiency. By the way, serves the electric motor / generator to increase the driving force of the motor support when the vehicle is started. If the electric motor / generator is used to runaway the engine as described above prevent, then the electric motor / generator must be controlled to prevent the engine from running away and then the engine to support. However, it is difficult to get correct or correct timing for the operation of the from the former aspect to the latter Aspect under this control / regulation switchable electric motor / generator to determine. If this timing is not correct and delayed then the driving performance of the vehicle is impaired.

On the other hand, in the Japanese mentioned above System Laid-Open No. 2000-272380 Control device which controls the engine throttle valve independently of the actuation of the accelerator pedal controls. Because of this requirement, it is Engine control system complicated. With this system it is necessary immediately after the start of engagement of the frictional engagement element Throttle opening of the engine quickly on one of the actuations of the Accelerator pedal to bring appropriate degrees. Therefore, a driver can do that Have a feeling that something is wrong.

To solve the above-mentioned problems, it is an object of the present one Invention to provide a power transmission control system which it enables a vehicle to run smoothly without an engine runaway to start after the engine is under a Idle elimination control has been stopped.

To achieve this, the present invention provides a vehicle power transmission control system comprising: an engine, a power transmission (e.g., the CVT continuously variable belt transmission described in the following description), a hydraulically actuated frictional engagement element (e.g. the starting clutch described in the following description) 5 , the forward clutch 25 and the reversing brake 27 ), an electric motor (for example the electric motor / generator M described in the following description) and a hydraulic pump. The engine is controlled to stop when the vehicle stops during an idling elimination control and the driving force transmission transmits a rotating driving force from the engine to the wheels. The hydraulically operated frictional engagement element controls the transmission of the rotary drive force in the drive force transmission, and the electric motor is provided closer to the motor than the frictional engagement element and can support the rotary drive of the motor. The hydraulic pump is connected to the output shaft of the engine and serves to apply an engagement operation pressure to the frictional engagement element. The power transmission control system performs the following control to restart the stopped vehicle with the engine stopped as a result under the idling elimination control. The control system causes the electric motor to rotate the output shaft of the motor, which in this case must not be supplied with fuel. The rotation of the output shaft driven by the electric motor actuates the hydraulic pump to supply hydraulic pressure to the frictional engagement element. When the frictional engagement element receiving the hydraulic pressure is ready for power transmission, the control system starts operating the engine so that the engine can generate torque. This control for starting the operation of the engine to generate a torque means either a control in which the engine is started when the frictional engagement element is ready for power transmission or a control in which the engine is started, just before the frictional engagement element is ready for power transmission, and when the frictional engagement element is ready for power transmission, the engine that has already started can provide actual drive torque.

According to a feature of this transmission control system drives the electric motor if the vehicle whose engine is running during the Idle elimination control has been stopped, restarted should first turn on the hydraulic pump, which is connected to the output shaft of the Motor is connected, which in this case receive no fuel may. In this state, the frictional engagement element receives from the pump discharged oil and when the frictional engagement element engages starts, the engine is started. After the frictional engagement element is ready for power transmission (i.e., it is currently engaged the output power of the engine is controlled by the Transfer frictional engagement element to the wheels to start the vehicle. On this way, the vehicle can run smoothly without going through the Motors are started. In this case, the electric motor only becomes Drive the hydraulic pump and turn the idling motor used so that there is no possibility that the electric motor is heated excessively. Therefore, this electric motor can be designed be miniaturized. If, in addition, the electric motor even after the start of the Motor is kept in operation, then the electric motor can be controlled / regulated to the engine to drive the vehicle too support. This is advantageous in order to improve the driving performance of the vehicle. Since no fuel was supplied in the initial stage of the control / regulation this fact contributes to an improvement in fuel efficiency.

Furthermore, the intake and exhaust valves of the cylinders of the engine can be so be constructed so that they can be kept closed. At this Arrangement will be made when the vehicle that is used during the Idle elimination control stopped with the engine stopped as a result has to be started again while the hydraulic pump is Operating electric motor is driven (i.e. while no Fuel is supplied to the engine), preferably at least some of the Intake and exhaust valves kept closed. Therefore none or little fresh air into the cylinders, while the output shaft of the Motor is rotated by the electric motor (while the motor is idling is rotated). This arrangement helps to clean the exhaust gas at the time hold when the motor is activated. By the inlet and Exhaust valves are kept closed, the pumping loss is also low held, which would otherwise occur to a great extent if the air flows through the passages of the intake and exhaust valves is likely while the pistons are reciprocating in the cylinders. This reduced loss leads to reduced electricity consumption, since the drive torque required by the electric motor becomes small. In addition, the vibration of the engine is relatively small because the intake and exhaust valves are not opened and closed.

According to another feature of the present invention, a other vehicle power transmission control system an engine, which can be controlled / regulated so that it stops when that Vehicle stops during idle elimination control, one Driving power transmission, which is a rotational driving force from the engine Transmits wheels, a hydraulically operated frictional engagement element, which is the transmission of the rotational driving force in the Driving power transmission controls, and a hydraulic pump which from the engine is driven to the engagement operation pressure Feed friction engagement element. This transmission control system leads the following control to regulate the vehicle again start, which stopped with during the Idle elimination control / engine stopped in a row. The Control system causes the engine to start in a state in which the output power of the engine by an ignition timing shift is reduced. After that the hydraulic pressure from the hydraulic pump receiving frictional engagement element is ready for a power transmission and the frictional engagement element starts its engagement process, the Engine ignition time reset to normal condition.

According to this power transmission control system, to start the engine stopped during idle elimination control to restart the vehicle the engine first with a Ignition time shift started (for example, the ignition time is delayed) by the Limit output power of the engine. Therefore the engine starts without any runaway of the engine and hydraulic pump, which of the engine operated in this state is driven by oil, which is fed to the frictional engagement element. If that's the oil receiving frictional engagement element begins its engagement, the Engine ignition time reset to a normal setting To increase the output power of the engine to a normal level, so that Vehicle can be started smoothly. In this case the Engine speed according to the accelerator pedal actuation controlled / regulated so that the driver feels no abnormality in operation.

This power transmission control system can be an electric generator be provided on the engine instead of the frictional engagement element, so that the Electric generator for generating electricity powered by the engine can be. While the engine, as described above, with the Ignition shift is operated, the electric generator can be used to generate Electricity powered by the engine. With this arrangement the Start of the engine safely protected against engine runaway, because the engine started with a shifted ignition time reduced Has output power and since the engine in this state also by the load of the electric generator is throttled to generate electricity. In In this case, if the frictional engagement element which is that of the Hydraulic pump receives discharged oil, actually starts its engagement, the ignition timing of the engine is reset to the normal setting and the Generation of electricity ended by the electric generator. To this Time will take the output power of the engine to a normal level reset so that the vehicle can be controlled to to start smoothly. Likewise in this case the engine speed controlled according to the operation of the accelerator pedal so that the driver feels no abnormality. Furthermore, since the electric generator only by one reduced output power generating motor is heated the electrical generator is never overly energized, so switching the Electric generators to stop electricity generation running smoothly he follows.

Another area of application of the present invention is that of following detailed description obvious. However, should be understood that the detailed description and special Examples, although showing preferred embodiments of the invention, are for illustration purposes only because of various changes and Modifications within the spirit and scope of the invention Those skilled in the art will be apparent from this detailed description.

The present invention will become more apparent from the detailed below Description and the accompanying drawings understood, which only are illustrative and thus not the present invention restrict. They represent:

Fig. 1 is a sectional view describing the construction of a power transmission which is of the present invention controlled by a control / regulating system according to / controlled;

Fig. 2 is a schematic diagram describing the transmission system of the power transmission;

Fig. 3 is a flow chart showing control / shows control steps, the control system executed by the transmission control / accordance with the present invention;

Fig. 4 is a timing diagram / control system is observed chronological changes in various parameters during operation of the control;

5 is a flowchart showing control steps performed by another power transmission control system as another embodiment according to the present invention; and

Fig. 6 shows a time chart observed during the operation of this second control / regulating system for different parameters chronological changes.

A preferred embodiment according to the present invention will be described with reference to the drawings. Fig. 1 is a sectional view describing the construction of a power transmission used for a vehicle, which power transmission of the present invention is controlled / regulated by a control / regulating system according to, and Fig. 2 shows schematically the power transmission system of this transmission. It is clear from these drawings that this power transmission includes an engine E, an electric motor / generator M connected to the output shaft Es of the engine E and a continuously variable belt transmission CVT connected to the output shaft Es of the engine through a clutch mechanism CP.

The engine E is a four-cylinder reciprocating piston engine and has a piston in each of the four cylinder bores 21 formed in a cylinder block 20 . The engine E is also equipped with an intake and exhaust control device 22 which controls the operation of the intake valves and the exhaust valves for each cylinder bore 21 , and with a fuel injection and ignition control device 23 which controls the fuel injection and the Ignition for each cylinder bore 21 controls. The electric motor / generator M supports the driving force of the motor when it is supplied with energy by a battery installed in the vehicle, and charges the battery by generating electricity from the rotary drive received from the wheel side while the vehicle is decelerating (energy recovery). Thus, this power transmission has a hybrid type drive source.

The continuously variable transmission CVT includes a metal V-belt mechanism 10 , a forward / reverse shift mechanism 20, and a start clutch (main clutch) 5 . The metal V-belt mechanism 10 is arranged around the input shaft 1 and the counter shaft 2 of the transmission and the forward / reverse switching mechanism 20 is arranged above the input shaft 1 and the starting clutch 5 is arranged on the counter shaft 2 . This continuously variable transmission CVT is attached to a vehicle, and the input shaft 1 is connected to the output shaft Es of the engine through a clutch mechanism CP. The driving force output from the transmission is transmitted through the starting clutch 5 to a differential mechanism 8 and then used to drive axle shafts 8 a and 8 b to turn right and left wheels of the vehicle (not shown). In addition, a hydraulic pump P is provided in the transmission case and is connected to the input shaft 1 through a chain mechanism cm. Therefore, the hydraulic pump P is driven by the input shaft 1 rotating at the same speed as the engine output shaft Es, so that oil is supplied to a control valve CV described in detail later in this section.

The metal V-belt mechanism 10 includes an over the input shaft 1 is arranged adjustable in the width drive pulley 11, an arranged on the countershaft 2 adjustable in width driven pulley 16, and disposed around these pulleys 11 and 16 around metal V-belt 15 °. The drive pulley 11 comprises a stationary pulley half 12 which is rotatably arranged on the input shaft 1 and a movable pulley half 13 which is movable with respect to the stationary pulley half 12 in the axial direction of the pulley 11 . On the lateral outside of the movable pulley half 30, a drive pulley cylinder chamber 14 is defined by a cylinder wall 12 a and a supplied by a control / regulating valve CV and through an oil passage 31 of the cylinder chamber 14 pulley control / regulating pressure generates a thrust which shifts the movable pulley half in the axial direction of Drive pulley moves.

The driven pulley 16 includes a stationary pulley half 17 which is fixed to the countershaft 2 and a movable pulley half 18 which is movable with respect to the stationary pulley half 17 in the axial direction of the pulley. On the lateral outside of the movable pulley half 18, a driven pulley cylinder chamber 19 is defined by a cylinder wall 17 a and a supplied by a control / regulating valve CV and through an oil passage 32 of the cylinder chamber 19 pulley control / regulating pressure generates a thrust which shifts the movable pulley half 18 in the Axis direction of the driven pulley shifts.

With this construction, the hydraulic pressures supplied to these cylinder chambers 14 and 19 of the drive pulley are controlled by the control valve CV to generate suitable lateral thrust forces in these two pulleys so that the belt 15 does not slip. Furthermore, these pressures supplied to the cylinder chambers are controlled in order to produce a difference in these lateral thrust forces, so that the groove widths of these pulleys change, which sets the pitch circle radii of the respective pulleys for the V-belt 15 . In this way, the gear ratio of the transmission is controlled / regulated in order to change continuously. These lateral thrust forces generated in the drive and driven pulleys for the ratio control are generated from a line pressure set by a regulator valve from the pressure of the hydraulic pump P, which hydraulic pump P connects to the input shaft 1 through the chain mechanism cm is. In particular, the pressure of either the drive or the driven cylinder chamber, which is the higher of the two, is generated from the line pressure.

The forward / reverse shift mechanism 20 is a planetary gear train that includes a sun gear 21 , a ring gear 22 , an idler gear 23, and a forward clutch 25 . The sun gear 21 is connected to the input shaft 1 and the ring gear 22 is connected to the stationary pulley half 12 of the drive pulley 11 . The idler gear 23 can be held against rotation by a reversing or reverse brake 27 and the forward clutch 25 can be actuated to connect the sun gear 21 to the ring gear 22 . In this mechanism 20 , when the forward clutch 25 is engaged, all of the gears 21 , 22 and 23 rotate together with the input shaft 1 as one body, and the drive pulley 11 is driven by the driving force of the motor E in the same direction as the input shaft 1 (i.e., in FIG the forward direction of the vehicle). On the other hand, the idler gear 23 is held stationary when the reverse brake 27 is applied so that the ring gear 22 rotates in the opposite direction to that of the sun gear 21 , and the drive pulley 11 is driven by the driving force of the motor E in the direction opposite to that of the input shaft 1 (ie in the reverse direction). The engagement process of the forward clutch 25 and the reversing or reverse brake 27 is controlled by a forward / reverse control pressure, which is set by the control valve CV from the line pressure.

The starting clutch 5 is a clutch to control the power transmission between the countershaft 2 and the output elements of the transmission, that is, the power transmission gears 6 a, 6 b, 7 a and 7 b. In the state in which the starter clutch 5 is engaged, the output power of the engine after experiencing the gear ratio change by the metal V-belt mechanism 10 becomes through the gears 6 a, 6 b, 7 a and 7 b the differential mechanism 8 and then transmitted by the differential mechanism 8 to the right and left axle shaft 8 a and 8 b and divided and then transmitted to the wheels. When the starting clutch 5 is released, this power transmission is ended, so that the transmission is in the neutral state. The engagement of the starting clutch 5 is controlled by a clutch control / regulating pressure, which is set by the control / regulating valve CV from the line pressure and is then fed through an oil passage 33 .

In this CVT continuously variable transmission, as described above, the drive pulley and the driven pulley from the control valve CV through the oil passages 31 and 32 , respectively, are used to control the transmission ratio change during the forward / Reverse control pressure supplied to the forward clutch 25 and the reverse brake 27 from the control valve CV through an oil passage (not shown) is used for the forward / reverse shift control of the transmission. In addition, the clutch control pressure from the control valve CV through the oil passage 33 is used to control the starting clutch engagement. To control these control pressures, the operation of the control valve CV, which receives oil from the hydraulic pump P, is controlled by control signals sent by an electrical control unit ECU.

In the vehicle containing this transmission, the electric motor / generator M supports the driving force of the engine E, so that the engine E can operate in an area which is extremely fuel efficient. In order to improve the fuel efficiency of the vehicle, the operation of the electric motor M is controlled by control signals sent from the electrical control unit ECU through a control line 36 . At the same time, the gear ratio change control is performed to achieve an optimal gear change ratio for operating the engine E in an extremely fuel efficient manner. This control is also carried out by control signals sent from the electrical control unit ECU through a control line 35 to the control valve CV.

Furthermore, the engine E can be operated in a partial cylinder operating mode, where some of the four cylinders are set in a standby state when a predetermined state for the vehicle is satisfied (for example, in the event of a deceleration). While the electric control unit ECU controls the operation of the intake and exhaust control unit 22 by control signals sent through a control line 37 and the operation of the fuel injection and ignition control unit 23 by a control line 38 / controls to operate the engine in a partial cylinder mode of operation, particularly keeps intake and exhaust valves closed for some cylinder bores 21 and prevents these cylinders from receiving fuel injection and ignition. By operating the engine in this manner, the fuel efficiency of the vehicle is improved especially during deceleration of the vehicle. In addition, the force of the engine brake is kept relatively small, so that the energy used for the deceleration is effectively recovered by the electric motor / generator M.

With this power transmission, an additional Idle elimination control performed to further increase fuel efficiency improve. The idle elimination control basically serves to stop the operation of the engine itself after the vehicle goes to the Has come to a standstill and when the driving force of the motor is unnecessary will, d. H. the engine enters an idling state. At the for this Power transmission executed idle elimination control is used to achieve a higher level of fuel efficiency in particular then when the accelerator pedal is released to decelerate the vehicle and to stop the fuel injection during the Delay ends and this condition becomes for the engine Maintain engine idle elimination.

In the power transmission with the structure described above, the engine is restarted to start the vehicle with the vehicle stopped during the idle elimination control. This start control will now be described with reference to the flow chart of FIG. 3 and the time chart of FIG. 4. With this control, it is first determined in step S1 whether or not an idle stop flag F (IS), which is set when the engine is stopped during the idle elimination control. If the idle stop flag is not set, ie F (IS) = OFF, which means that the engine is in operation, the control flow ends here. Conversely, if the idle stop flag is set, F (IS) = ON, then the control flow goes to step S2, where another determination is made as to whether an engine start flag is set or not, ie, F (ES) = ON. This engine start flag is set when the engine should be started to move the vehicle. If the engine start flag is not set, ie F (ES) = OFF, which means that the engine does not start, the control flow ends here.

Conversely, if the result of the determination in step S2 is that the engine start flag is set, that is, F (ES) = ON, then a cylinder out request control is started in step S33, in which the intake and exhaust valves of the engine E are kept closed and fuel injection and ignition are stopped. Then, the control flow goes through step S4 to step S5 until a determination in step S4 gives a result that the preparation for engaging the clutch is completed. In step S5, the electric motor / generator M is used as an electric motor to drive the output shaft Es of the motor by rotation. For example, the brake pedal is released and then the accelerator pedal is pressed after the engine stops during the idle elimination control. As shown in FIG. 4, the engine start flag is set, that is, F (ES) = ON, at time t0. From this point on, the cylinder-off control / regulation for the engine is carried out and the electric motor / generator M is started at time t0.

After the intake and exhaust valves have been closed by the cylinder-off control / regulation, the electric motor / generator M drives the output shaft Es of the engine. In this way, the friction torque of the motor E is made small to minimize the consumption of electricity by the electric motor / generator M. In addition, no fresh air is drawn into the cylinders of the engine. This helps to clean the exhaust gas generated at the time the engine E is activated. The operation of the electric motor / generator M is set in a start mode during the time period from time t0 to time t1, where it generates a starting torque to increase the speed of the output shaft Es of the engine, and then in an idle mode for the time period from time t1 is set at time t2, where the electric motor / generator M drives the output shaft Es of the motor idling. Therefore, the motor torque of the electric motor / generator M is controlled as shown in FIG. 4. In response, the speed Ne of the output shaft Es of the motor driven by the electric motor / generator M gradually increases to a predetermined idling speed, and this speed Ne is kept constant for a while.

In the control valve CV, a linear solenoid valve (not shown but it is provided in the control valve CV) that generates the clutch pressure Pc supplied to the start clutch 5 through the oil passage 33 is operated at time t0 when the engine start flag is set, ie F (ES) = ON, and then controlled as shown in Fig. 4. In particular, in this control / regulation, the linear solenoid valve receives control signals which serve to generate changes in the clutch pressure Pc, as indicated by the solid line A in the time diagram. However, the actual changes occurring at the clutch pressure Pc are as indicated by the broken line B. Here, since the speed of the output shaft Es of the engine starts to increase from the time t0 to the idling speed, as mentioned above, the rotation of the input shaft 1 , which is connected to the output shaft Es and rotates together with it at the same speed, is caused by the chain mechanism cm to the hydraulic pump P, which drives the pump P. Therefore, the oil discharged from the pump P is supplied to the control valve CV, which is then supplied from the linear solenoid valve through the oil passage 33 to the starting clutch 5 . In particular, the oil from the pump is first fed directly to the starting clutch through the linear solenoid valve until the oil passage 33 and the oil chamber of the starting clutch 5 are filled with the oil. After its fulfillment, the result of the determination in step S4 is that the engagement preparation for the starting clutch 5 has been completed (time t2). This determination is made by detecting a counter electromotive force generated in the solenoid of the linear solenoid valve in response to a change in the hydraulic pressure supplied from the linear solenoid valve.

After completion of the engagement preparation of the starting clutch 5 (time t2), the control flow goes to step S6, where the engine E is controlled to start. In this control, after the lapse of the time set in a timer to determine completion of the engagement preparation from time t2, that is, at time t3, the cylinder-off request control is ended to start the engine E and the idle stop flag is reset, ie F (IS) = OFF, in step S7. Thereafter, the speed of the engine E increases according to the depression of the accelerator pedal, as shown in FIG. 4. In this case, if the driving force of the motor is insufficient, the motor E is supported by the electric motor / generator M in order to ensure a desired starting behavior in step S9.

Likewise, the linear solenoid valve receives a control signal after the end of the preparation for engagement of the starting clutch 5 at time t2, which increases the clutch pressure rapidly, as shown in FIG. 4 in step S8. This serves to quickly eliminate the improper stroke of the piston in the starting clutch 5 . Therefore, the improper stroke of the starting clutch 5 is eliminated so that it starts the actual engagement. Thereafter, the clutch pressure is controlled to gradually increase.

The control for starting the engine, which was stopped during the idle elimination control, is carried out in the above-described steps, namely, first, the output shaft Es of the engine in the cylinder-off control is driven by the electric motor / generator M. and after completion of the engagement preparation of the starting clutch 5 , the engine is started. In this way, the starting clutch 5 is smoothly engaged without the engine going through, so that the vehicle is started smoothly. In the control described above, the engine E is started after completion of the engagement preparation of the starting clutch 5 . However, the engine E can be controlled to be started after completing the elimination of the improper stroke of the starting clutch 5 . Preferably, the start of the engine can be timed to be something before the completion of the engagement preparation of the start clutch or the completion of the improper stroke of the start clutch 5 so that the engine E can provide drive torque at the time when the engagement preparation the starting clutch 5 is completed or the elimination of the incorrect stroke of the starting clutch 5 is completed.

Another control for starting the engine for starting the vehicle, which was stopped during the idle elimination control, will now be described with reference to the flowchart of FIG. 5 and the timing chart of FIG. 6. Likewise, in this control, a determination is first made as to whether the idling stop flag is set, ie F (IS) = ON, or not in step S21. If the idle stop flag is not set, ie F (IS) = OFF, which means that the engine is in operation, the control flow ends here. Conversely, if the idle stop flag is set, F (IS) = ElN, then the control flow goes to step S22, where another determination is made as to whether or not the engine start flag is set, ie F (ES) = ON. If the engine start flag is not set, ie F (ES) = OFF, which means that the engine has not started, the control flow ends here.

Conversely, if the result of the determination in step S22 is that the Engine start flag is set, d. H. F (ES) = ON, then the motor E with an ignition delay (which delays the ignition time) by the Output power of the motor E at a low level in step S23 to keep. The engine E is operated with the ignition delay until one Determination in step S24 indicates that the preparation for the procedure the clutch is complete.

On the other hand, a linear solenoid valve provided in the control valve CV to generate the clutch pressure PC which is supplied to the start clutch 5 through the oil passage 33 is operated at time t0 when the engine start flag is set, that is, F (ES) = ON, and then controlled. Since the engine E is operated with the ignition delay after the time t0, the hydraulic pump P is driven by the chain mechanism cm by the rotation of the output shaft Es of the engine. Therefore, the oil discharged from the pump P is supplied to the control valve CV, which is then supplied from the linear solenoid valve through the oil passage 33 to the starting clutch 5 . When the oil passage 33 and the oil chamber of the starting clutch 5 are filled with the oil, a determination in step S24 results in that the engagement preparation for the starting clutch 5 is completed (time t2).

After completion of the engagement preparation of the starting clutch 5 (time t2), the control flow goes to step S25, where control for eliminating the ignition delay is performed so that the engine E will operate normally (the ignition time is returned to the original value reset). This control after the lapse of the time set in a timer for determining the completion of the engagement preparation from the time t2, that is, at the time t3, increases the output power of the engine E and resets the idling stop flag, that is, F (IS) = OFF, im Step S26. Thereafter, the speed of the engine E increases according to the depression of the accelerator pedal, as shown in FIG. 6. In this case, if the driving force of the motor is insufficient, the motor E is supported by the electric motor / generator M in order to ensure a desired starting behavior in step S28.

After completion of the engagement preparation of the starting clutch 5 at time t2, the linear solenoid valve receives a control signal which rapidly increases the clutch pressure, as shown in FIG. 6 in step S27. This serves to quickly eliminate the improper stroke of the piston in the starting clutch 5 . Therefore, the improper stroke of the starting clutch 5 is eliminated so that it starts the actual engagement. Thereafter, the clutch pressure is controlled to gradually increase as shown in the time chart.

The control for starting the engine, which was stopped during the idling elimination control, is carried out in the above-described steps, namely, the engine E is started with an idling delay with its output power being damped, and after completion of the engagement preparation of the engine Starting clutch 5 , the engine is released from the ignition delay, so that its output increases while the starting clutch 5 is engaged. In this way, the starting clutch 5 is smoothly engaged without the engine going off, so that the vehicle is started smoothly. In the control described above, the engine E is released from the ignition delay after completion of the engagement preparation of the starting clutch 5 . Instead, the engine E can be started when the removal of the improper stroke of the starting clutch 5 has ended.

The above embodiments are described with respect to the engagement control of the starting clutch 5 . However, the present invention is not limited to the control of the starting clutch 5 . The present invention can also be applied to the forward clutch 25 and the reverse brake 27 in the same manner. In the above embodiments, a continuously variable transmission with a metal V-belt mechanism 10 is used as an example, but any other type of continuously variable transmission or a gear type automatic transmission can be used in the same manner instead.

As described above, according to a feature of the present Invention to start the engine, which during a Idle elimination control has been stopped, first start the vehicle hydraulic pump connected to the output shaft of the engine an electric motor driven without a fuel supply to the engine, so that oil discharged from the pump is a frictional engagement element is fed. After the frictional engagement element, which is the oil receives, is ready for a power transmission, the engine is started. By the frictional engagement element that started the engagement becomes the Output power from the engine to the wheels, so that Vehicle is started. This way the vehicle will run smoothly without a runaway of the engine started. In this case, the electric motor used to drive the pump and idle the engine to drive, so the electric motor the drive torque, which is the sum the pump drive torque and the motor friction torque, must provide. The torque required is not so great that it heats up the electric motor so that the size of the electric motor is small can be held. If, in addition, the operation of the electric motor too after the engine starts, then the electric motor can be controlled / regulated to the engine for improved driving performance to support the vehicle. With this control system, the Starting the engine does not supply fuel, reducing fuel efficiency of the vehicle is relatively high.

To start the vehicle whose engine is running Idle elimination control has stopped, it is preferable that the intake and exhaust valves are kept closed while the Hydraulic pump is driven by the electric motor. This way no fresh air into the cylinders during the engine output shaft the electric motor is driven. This helps the engine clean the exhaust gas hold when the motor is activated. Furthermore, since the inlet and Exhaust valves are closed, the pumping loss, which in one large scale would occur if the air passed through the channels of the Intake and exhaust valves should flow while the pistons in the Cylinders back and forth, kept small. This leads to a improved fuel efficiency. Since there is also no opening and closing of the Intake and exhaust valves occur, the vibration of the engine is relative low.

According to a further feature of the present invention, Starting the engine, which during idle elimination control / control has been stopped, the engine is started with to start the vehicle a shift in ignition timing (e.g. a delay in ignition timing) started to reduce the output power of the engine to a reduced level to restrict. As a result, the engine starts without going through the Engine and a hydraulic pump driven by the engine discharges oil, which is fed to a frictional engagement element. After that Oil-receiving frictional engagement element is ready for power transmission the ignition time of the engine to increase the output power of the Motors to a normal level to the original setting reset so that the vehicle can be controlled so that it starts smoothly. In this case, the speed of the motor is according to the Operation of the accelerator pedal controlled / regulated so that the driver does not Abnormality of operation feels.

An electric generator can be used with this power transmission control system be provided on the engine instead of the frictional engagement element, so that the electric generator driven by the motor generate electricity can while the engine is operating in the ignition shift. With This arrangement makes the engine safe from engine runaway protected because of reduced ignition timing Output power started by the load of the electric generator Generation of electricity is further throttled. In this case the ignition time the engine to its original setting and the Electricity generation by the electric generator stops when that Frictional engagement element, which is carried out by the hydraulic pump Receives oil, actually begins its engagement. Since the output power of the Motor can be reset to the original normal state the vehicle is controlled / regulated so that it starts smoothly. There the electric generator from the engine with a reduced Output power is driven, the electric generator never overheats, so that the switching of the electric generator to end the Electricity generation is smooth. Likewise, with this arrangement Engine speed according to the accelerator pedal actuation controlled / regulated so that the driver feels no abnormality.

It is apparent that the invention so described is in many ways can be varied. Such variations are not considered a departure considered from the spirit and scope of the invention and all such Modifications, as would be obvious to a person skilled in the art, are said to Scope of protection of the following claims may be included.

A vehicle power transmission control system comprises a continuously variable transmission CVT, which transmits the output power of an engine E to wheels, a starting clutch 5 , which controls the power transmission in the continuously variable transmission, an electric motor / generator M, which can support the engine in the rotary drive and a hydraulic pump P connected to the output shaft Es of the engine E. When the vehicle that has stopped with the engine subsequently stopped under an idling elimination control is restarted, the power transmission control system controls the electric motor / generator M to rotate the output shaft Es of the engine M to which no fuel supply is allowed so as to drive the pump P. Then, when the starting clutch 5 receiving hydraulic pressure from the hydraulic pump P starts to engage, the power transmission control system starts operating the engine E.

Referenced applications

This application claims priority from October 17, 2001 Japanese Patent Application No. 2001-318946, which is incorporated herein by reference.

Claims (7)

1. A vehicle power transmission control system comprising:
an engine (E) that can be stopped when the vehicle stops during an idle elimination control;
a driving force transmission (CVT) that transmits a rotating driving force from the motor (E) to wheels;
a hydraulically operated frictional engagement element ( 5 ) which controls the transmission of the rotational driving force in the driving force transmission (CVT);
an electric motor (M) which is provided closer to the motor (E) than to the frictional engagement element ( 5 ) and which supports the motor (E) in the rotary drive; and
a hydraulic pump (P) which is connected to an output shaft (Es) of the engine (E) and which supplies an engagement operation pressure to the frictional engagement element ( 5 );
in which:
the engine (E) is driven to restart the vehicle after the engine (E) stops as a result of the vehicle stopping during idle elimination control to drive the hydraulic pump (P) the output shaft (Es) with only a small limited amount Output torque to rotate; and
when the frictional engagement element ( 5 ) receiving hydraulic pressure from the hydraulic pump (P) is ready for power transmission, the motor (E) is operated to generate a torque. 2. The vehicle power transmission control system according to claim 1, characterized in that when the vehicle that has stopped during the idle elimination control is restarted with the engine (E) accordingly stopped, the engine output is made small by not supplying fuel to the engine Motor (E) is allowed;
that the output shaft (Es) of the motor (E) is driven and rotated by the electric motor (M) to drive the hydraulic pump (P); and
that when the frictional engagement element ( 5 ) receiving the hydraulic pressure from the hydraulic pump (P) is ready for power transmission, the fuel supply to the engine (E) is restarted so that the engine (E) is operated to generate torque , 3. Vehicle power transmission control system according to claim 2, characterized in that the engine (IE) has an intake valve and a Exhaust valve includes for each of its cylinders, the Inlet valve and the outlet valve can be kept closed; and that if the vehicle that was used during the Idle elimination control has stopped accordingly stopped engine (E) is to be restarted while the Hydraulic pump (P) from the electric motor (M) in operation is driven, at least some of the intake and exhaust valves be kept closed. 4. Vehicle power transmission control system according to claim 2, characterized in that while the engine output power is kept small by not supplying fuel to the engine (E) allowed and while the output shaft (Es) of the motor (E) is driven and rotated by the electric motor (M) to the To drive hydraulic pump (P), the electric motor (M) is controlled to a speed of the output shaft (Es) of the engine (E) gradually increase to an engine idle speed and then keep the engine speed (E) at this engine idle speed. 5. The vehicle power transmission control system according to claim 1, characterized in that when the vehicle that has stopped during the idle elimination control is to be restarted with the engine (E) accordingly stopped, the engine (E) is started in a state in which the output of the engine (E) is made small by an ignition timing shift, thereby reducing the output of the engine (E); and that when the frictional engagement element ( 5 ) receiving the hydraulic pressure from the hydraulic pump (P) is ready for power transmission, the ignition timing of the engine (E) is reset to a normal state so that the engine (E) is operated that a normal torque is generated. 6. The vehicle power transmission control system according to claim 5, further comprising an electric generator (M) which is provided closer to the engine (E) than the frictional engagement element ( 5 ) and which is driven by the engine (E) to generate electricity; characterized in that during operation of the engine (E) with the ignition timing shift the electric generator (M) is driven by the engine (E) to generate electricity. 7. The vehicle power transmission control system according to claim 1, characterized in that the hydraulic pressure from the hydraulic pump (P) is supplied to the frictional engagement element ( 5 ) through a linear solenoid valve; and a state in which the frictional engagement element ( 5 ) is ready for power transmission is detected from a counter electromotive force detected in a solenoid of the linear solenoid valve in response to a change in the hydraulic pressure supplied to the frictional engagement element ( 5 ).